Cost of Capital: Definition, Formula, WACC Calculation & Examples

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    Tally Solutions

    Updated on May 25, 2026

    Definition of Cost of Capital

    Cost of Capital is the rate of return the firm expects to earn from its investment in order to increase the value of the firm in the market place. In other words, it is the rate of return that the suppliers of capital require as compensation for their contribution of capital. Cost of Capital 

    Source of Cost of Capital

    The source of capital employed by the firm is usually in the following form:

    Source of Cost of Capital

    3 Components of Cost of Capital: Zero Risk, Business Risk & Financial Risk

    There are three factors to the cost of capital explained below:

    Zero Risk Return

    It talks about the expected rate of return when a project involves no financial or business risks.

    Premium for the Business Risk

    Business risk is determined by the capital budgeting decisions that a firm takes for its investment proposals. So, if a firm selects a project that has more than normal risk, then it is obvious that the providers of capital would require or demand a higher rate of return than the normal rate.

    Thus the premium factor plays an important role here as it increases the Cost of Capital. But how much premium? it’s up to the firm’s project selection decision which alienates with the firm’s goal and objectives and how badly they want the project to increase their market value. 

    Premium for the Financial Risk

    Financial risk is associated with the capital structure pattern of the firm. Here, the premium finds its way to the picture depending on the volume of debts the firm owes. The higher the debt capital, the more is the risk compared to a firm that has relatively low debts.

    Cost of Capital Formula

    The three components of cost of capital discussed above can be written in an equation as follows:

    K = Cost of Capital

    r0 = Return at zero risk level

    1. = Premium for business risk
    2. = Premium for finance risk

    How to Calculate Cost of Capital: Specific Cost vs WACC

    In calculating the cost of capital, the following methods can be used:

    1. Computation of Specific Cost of Capital

    Specific Cost refers to the cost which is associated with the source of capital. Eg. Cost of equity. Computing specific cost of capital involves summing up of all forms of capital listed below

    1. Computation of Composite Cost of Capital

    Composite capital is the combined cost of different sources of capital taken together. It is also called a Weighted Average Cost of Capital (WACC). Following are steps involved in the calculation of WACC. The formula to arrive is given below:

     

    Ko = Overall cost of capital

    Wd = Weight of debt

    Wp = Weight of preference share of capital

    Wr = Weight of retained earnings

    We = Weight of equity share capital

    Kd = Specific cost of debt

    Kp = Specific cost of preference share capital

    Kr = Specific cost of retained earnings

    Ke = Specific cost of equity share capital

     

    Looks bookish? We have got it simplified with the example.

    Cost of Capital Calculation Example with WACC Formula

    Aero Ltd had the following cost capital structure employed for financing its projects and would like to calculate the cost of capital.

     

    Amount ( Rs. )

    After-tax Cost %

     

    Equity share capital

    8,00,000

    16%

    0.0225

    Retained earnings

    4,00,000

    15%

    0.03

    Preference share capital

    6,00,000

    12%

    0.025

    Debentures

    6,00,000

    9%

    0.053

     

     

     

     

    Total

    24,00,000

     

     

     

    Calculation of Cost of capital of Aero Ltd

    Source

    Amount (Rs. )

     

     

     

    (1)

    Weights (Specific Capital/Total cost)

     

    (2)

    After-tax Cost (Cost%/100)

     

     

    (3)

    Weighted Cost

     

     

     

    (4) = (2) *(3)

    Equity share capital

    8,00,000

    0.34

    0.16

    0.053

    Retained earnings

    4,00,000

    0.16

    0.15

    0.024

    Preference share capital

    6,00,000

    0.25

    0.12

    0.03

    Debentures

    6,00,000

    0.25

    0.09

    0.023

     

     

     

     

     

    Total

    24,00,000

     

     

    0.13

     

    Weight Average Cost of Capital here is 13% (0.13*100). This implies that the overall cost of capital employed by Aero Ltd is 13%. In other words, we can say that the company is paying a premium of 13% to the lenders of capital as a return for their risk.

    You can use the formula we discussed, and the result will be similar.

    = (6,00,000 / 24,00,000) * 0.09 + (6,00,000 / 24,00,000) * 0.12 + ( 4,00,000 / 24,00,000 ) * 0.15 + ( 8,00,000 / 24,00,000) * 0.16 = 13%

    Determining Cost of Capital is one of the key factors in deciding the investment. It helps you in evaluating the different investment projects basis the cost, benefits and risks. Another important factor to be considered here is capital budgeting and payback period. Here, the payback period is nothing, but the time taken to recover the investment amount. Read "What Is Capital Budgeting? Process, Calculation and Example to know the process and calculations.

    Published on January 14, 2020

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